Cadillac Catera and Cimarron Forum Discussion, Grr after i thought things were going good with this car.. Need help with these codes in Past Cadillac Vehicle Discussion; I recently have been noticing a rough idle and loss of power in acceleration, car stumbling ect on my 98 ...

Grr after i thought things were going good with this car.. Need help with these codes

I recently have been noticing a rough idle and loss of power in acceleration, car stumbling ect on my 98 caddy.

The codes that are coming up are

p0300(random misfire)

p0302 misfire(cylinder 2)

p0304 (cylinder 4)

p0306 (cylinder 6)

Anyone that has had these codes come up on their caddy know exactly what is was? I changed my spark plugs about 3 months ago (NGK type), and when I changed my spark plugs, I also put in new valve cover gaskets as well due to an old leak; but that is not an issue anymore. What concerned me was a slight tear in the middle boot of the spark plug, at the very bottom of it ( the one on the right hand side of the valve cover).

Could this have been enough to cause a misfire? I took the boot out and a tiny bit of oil was around it from the leak before, but I cleaned most of it out when replacing the bad gaskets. I also had a bad oil leak before that traveled down to the catalytic converter, could this have damaged my o2 sensors creating a misfire?

Re: Grr after i thought things were going good with this car.. Need help with these c

Another thing to add, I cleaned the air flow sensor not too long ago, as well as the openeings to the throttle body about two weeks ago so I am not sure if the misfire has anything to do with the intake system, but I could be wrong. I also checked all my vacuume lines and they all appear to be connected correctly.

Re: Grr after i thought things were going good with this car.. Need help with these c

Originally Posted by ccatera10

Another thing to add, I cleaned the air flow sensor not too long ago, as well as the openeings to the throttle body about two weeks ago so I am not sure if the misfire has anything to do with the intake system, but I could be wrong. I also checked all my vacuume lines and they all appear to be connected correctly.

ccatera10 it appears all your codes are coming from the left or driver side bank (cylinders 2, 4 and 6) of cylinders.

The search should be on any elements common to the left bank. I know I had similar issue in my 2001 Catera but in the right hand bank (cylinders 1, 3 and 5). In my case in heavy rain wet weather I got problems like yours. There was a tear in the scuttle right above the coil pack and water used to drip/pour during heavy rain and spalshes. I re-installed the coil pack and used GM dielectric grease all around the modules and sealed as well as the electrical connectors. I never had the problem again. I was told about it by a GM service advisor.

It is an area worth checking and sealing properly as well as Mcgiver fix any tears in the scuttle. Beyond that I cannot think of much right now.

Re: Grr after i thought things were going good with this car.. Need help with these c

Originally Posted by ccatera10

To the previous poster, I think this has little to do with my engine misfire.

Anyone else had misfire issues with their catera?

If you have water build up due to the clogged scuttle drains then the path of least resistance (where the water will end up) is right over your coil, in turn dripping on and shorting them. I had this same issue on a customer's 2001 mercedes s600, the water would collect and drip on the coil pack. (it's a coil on plug style more like the 99up cateras) The water would then short the elements and that became a BIG bill. Mercedes quoted something like 5k just for a right bank coil replacement. Cost me nearly 1k just for the coil. I guess what I'm really getting at is yes, blocked water can cause a coild to go bad and in turn cause a miss.

Re: Grr after i thought things were going good with this car.. Need help with these c

Ah, didn't check out the link, that's just a heater core flush. I could check your drains though. I live in a wooded area so I clean mine every season (4x's a year). One is visible when you pop the hood on the driver's side, the other is down below the cabin filter.

Re: Grr after i thought things were going good with this car.. Need help with these c

ccatera10 .... if your are getting oil inside the oil well causing the spark plug boot as well as the top of the spark plugs to be soaked in oil then you definately have a bad valve cover. Mine had that issue which means the valve cover where leaking on the inside part which ends up inside your spark plug wells.

Re: Grr after i thought things were going good with this car.. Need help with these c

That is most likley the problem. The thing is i changed the valve covers about 2 times since i had the car all done right and i guess oil is prone to get into this area, as far as my catera goes. i guess it may be those little ring gaskets that are loose, because no sign of spilling is present outside of the valve covers.Anyway i am too tired of spending money and time on this car so i guess i am just sending it to car hell aka the junk yard after the ordeal it gave me today.